Again, there are also explicitly correlated and local variants of many of these methods, see
sections 18 and 17, respectively.

Note that all methods except ump2 use spin-restricted Hartree-Fock (RHF) reference functions.
This is also the case for the ucisd and uccsd methods, in which the correlated
wavefunction may be slightly spin contaminated, even though the
RHF reference function is spin adapted.
ump2 is not generally recommended,
since spin contamination can lead to large errors.

Core orbitals can be specified as for the closed-shell methods. The number of electrons and
occupations as well as the orbitals are taken from the most recent RHF calculation.
It is possible to modify these defaults using occ, closed, wf, or orbital
directives; see the MOLPRO reference manual for details.